People who buy Olympic souvenirs in the hope they might one day be worth a fortune should take a breath and count to 10 before parting with their money, an expert said Tuesday.

Li Xiang, from the China Association of Collectors, said that although the value of some items might soar at first, interest in them will almost certainly decline over time.

In 1997, for example, commemorative coins issued to mark the return of Hong Kong to the mainland were selling for up to 500 yuan ($73) apiece shortly before the event, but soon after, their value fell to less than 20 yuan, Li said.

"People should pay more attention to the cultural and historical value of the items they collect," he said.

"Investing in Olympic souvenirs may bring big profits, but it is also high risk."

Xiao Lin from Shanghai, who has been collecting Olympic souvenirs for 15 years, said: "The value of most collector's items depends on how many of them there are in circulation."

Currently, the hottest Olympic souvenir is the commemorative 10-yuan banknote issued by the People's Bank of China," he said.

"There were only 6 million of the notes produced, and they are now changing hands for up to 1,000 yuan apiece, 100 times their face value."

But not all items are such good investments.

An anonymous stallholder at a stamp market in Guangzhou said the value of some Olympic stamps issued just months ago has already fallen by more than 50 percent.

Nevertheless, with more than 7,000 BOCOG authorized souvenirs - from gold bars to tiepins - on offer, there is plenty of choice for would-be collectors and investors.

Wang Xingyun, an amateur collector from Tianjin, said: "Olympic souvenirs are quite meaningful for Chinese people, as they are an everlasting memento of the Beijing Games.

"The first thing I bought was a pin to mark the 400-day countdown," the 24-year-old postgraduate student said.

Although Wang did not initially regard the pin as an investment - he said his interest was pricked by the quality of the craftsmanship and the cultural value - he was nonetheless delighted to discover it had soared in value.

"I bought the pin for just 36 yuan, but I've been told that it could now be worth as much as 500 yuan," he said.